Louise works as a waitress in a Chinese restaurant in the Notre-Dame-de-Grâce neighborhood of Montreal, where she spends her days and nights immersed in the latest newspaper coverage of a string of brutal serial murders and rapes in the area. She pours over each victim’s story, searching for clues, and the pattern begins to haunt her when the newest victim turns out to be a coworker who had mentioned a blond, muscular man she had met at a bar and who had a drink with her after she finished her shift at midnight. That detail grips Louise with growing fear, nudging her toward a darker vigilance about the people around her. Her quiet world is already colored by the companionship of her two cats, Tia Maria and Mozart, who share the small apartment with her and bluntly remind her of the loneliness that human company rarely fills.
Louise’s neighbor, Spencer, uses a wheelchair and keeps a careful distance from others, valuing his privacy and solitude even as he is drawn into the orbit of his neighbors’ concerns. Across the hall lives Victor, an awkward, talkative elementary school teacher who has recently moved into the building and quickly ingratiates himself with Louise and Spencer. Victor’s presence adds a new energy to Louise’s routines; he becomes the person she allows to walk her home after a shift, especially on nights following the murder of her coworker, when a police officer’s questions echo the fear in her statements and she feels the most exposed.
As the days unfold, Spencer reveals more about his own past—he was paralyzed in a car accident that killed his wife—and he rejects Victor’s sympathy, revealing a blunt, unyielding temperament. He even reacts with anger when Victor tries to make the building more accessible with a wheelchair ramp, underscoring a sharp unease between his private life and the changing dynamics around him.
Victor, who has developed a crush on Louise, imagines a life with her that goes beyond friendship, even telling his brother at a party that they are engaged. At that same party, Victor presents his cat from China, Balthazar, which is brought over after customs quarantine and becomes an instant focus of Louise’s affection. Louise, for her part, is drawn to the cat and to the idea of a growing closeness with Victor, who begins to show her warmth as she helps him navigate the uneasy currents in their building.
Meanwhile, Spencer slips out at night through the fire escape to enjoy the city’s nocturnal life, an act that looks ordinary to him but soon takes a disturbing turn when he is seen in the act of a sexual encounter with a woman who appears dead. The morning after, one of Victor’s friends spots Spencer, and Victor dismisses the idea that it could be him, trying to maintain his confidence about the fragile web of friendships in the building.
The tension thickens when Valérie, a harsh Francophone neighbor whose cruelty has been noted, poisons Louise’s cats on Christmas morning, deepening Louise’s sense of vulnerability and isolation. In the wake of the loss, Louise spends even more time at Victor’s apartment, preferring the company and quiet of his place, and even taking Balthazar with her to her own home.
Driven by sensationalist media reports, Louise begins to plot revenge against Valérie, who she holds responsible for the tragedy that has unspooled in their building. She seduces Victor and collects a sample of his semen, which she carefully saves for later use. After cleansing herself, she visits Spencer for a drink and flirts with him again, blurring lines and deepening the undertow of danger in their shared space.
Louise calls in sick from work, then launches her plan to frame Valérie for murder by using Victor’s semen to fabricate evidence of rape and murder. She violates Valérie’s corpse in order to plant the sample in a way that echoes the serial killer profile she has been watching unfold in the headlines. Returning home, she encounters Spencer, who has decided to go out, and she hands him her bag of “evidence” to exchange the murder kit for him—an exchange that leaves him surprised but willing to help. Victor, looking out his window, notices the exchange and begins to suspect that Spencer may be the killer after all.
A tense arrangement forms as Victor, now wary of Spencer, intervenes with Louise before she heads to Spencer’s door. He explains what he has told the police and reveals his own suspicions about Spencer, proposing a plan to trap him. Spencer, in turn, hints at framing Victor, unaware that Louise has already spoken with Victor and that he, Victor, intends to turn the danger back onto Spencer. The two men’ s plans collide as Spencer arranges a dinner party intended to serve as a trap.
Louise, keeping a careful watch, leaves Victor’s window open as part of Spencer’s plan, and soon a patrol car of investigating officers sits across from the building. The plan unfolds: Spencer bursts into Victor’s apartment, the police rush in on their tips, and Victor confronts him while chasing him onto the fire escape. Spencer tries to reveal the truth about who killed Valérie, but Victor lashes out and kicks him, sending him off the fire escape to the snow below. Louise, meanwhile, shows almost disinterested indifference to the escalating confrontation, returning to the safety of caring for Tia Maria and Mozart as she feeds the cat and smiles at Spencer’s rage from a distance.
As Victor looks down at Spencer bleeding in the snow, an officer urges him to call 911, and the moment crystallizes the tragedy of the night. The same officer affirms that Victor did the right thing, while Louise quietly acts on her own agenda—she opens the window for the cat, slips into Spencer’s apartment, and climbs onto the top of his fish tank, leaving the fate of the night’s tangled web unresolved in a way that lingers in the imagination.
